It’s rare to see a player of Sam's quality, with almost 150 Bundesliga games and two seasons of Champions League football under his belt, move to a domestic rival that isn't Bayern Munich. Yet this summer, the Germany international did just that when he swapped Bayer Leverkusen for Schalke.

What’s more surprising, though, was the shrewd and cunning business Die Königsblauen pulled off in signing such an experienced and talented player for just €2.5 million – all thanks to a pitiful release clause in the player's five-year deal at the BayArena. Leverkusen still somehow made a profit on Sam, after signing the winger for just €2.2m from Hamburg in 2010.

He missed 11 games last season through injury, but Sam was still seen as one of Leverkusen’s best players in an up-and-down campaign. He scored seven goals and assisted four in the first nine games, but ended with his tally beefed by only one more net-rippler. "I’m aiming for 15 goals, more than I’ve had before in a season," he declared in the summer. Don't put it past him.

Why do you need to know him

The Bundesliga has been a stomping ground for players with magical left pegs over the last few years. The likes of Juan Arango, Arjen Robben, Ivica Olić, Son Heung-min and Ricardo Rodriguez are all well known for their deadly deliveries, and Sam too features high on the list.

As is custom in the modern game, Sam mostly operates from the right, and naturally enjoys cutting inside to let loose on his stronger foot. He’s also confident with his weaker foot, however, as he told Bild.

"I don’t mind where I play," he declared. "Right, left, or in the middle. I consider myself two-footed, so I’m happy wherever." With that, he gives defenders a worry they don’t usually have with the likes of Robben and Mesut Özil – both reliant on their stronger side.

As Chelsea prepare to welcome the German and his Schalke team-mates in the Champions League this week, you might find it strange to hear of previous bad blood between Sam and the Premier League title favourites.

Before the Blues faced Bayer Leverkusen in the 2011 Champions League, Sam decided to spice up pre-game discussions with a picture of himself, thumb down in front of a Chelsea shirt at a sports shop.

Not much should be made of the picture itself, but the caption alongside it on his Facebook page - “who the f*** is chelsea london ?!?!” – made a lasting impression. As expected, the winger bore the brunt of stick that night in the west Londoners' 2-0 win.

Sam netted twice in the Champions League for Leverkusen last season

Strengths

Zinedine Zidane was the master technician of his generation, with his goal in the 2002 Champions League Final against Sam’s former club Leverkusen epitomising the Frenchman's brilliance. Since that strike, not many can say with great confidence that they’ve come close to matching the effort. Sam’s against Kaiserslautern in 2011, however, was pretty close (see video below).

As well as his ability to score from various positions, Sam has nailed down the key attributes of a modern winger: pace, effective dribbling and an eye for goal combine to make him a dangerman whenever he plays.

In a team featuring Julian Draxler, Max Meyer and Kevin-Prince Boateng, Sam is by far the biggest contributor in terms of chance creation. He’s set up his team-mates for eight so far this season, which is twice as many as any other Schalke player.

Chelsea can also expect plenty of link-up play between Sam and the right-back behind him on the pitch – in Saturday's 4-1 defeat to Borussia Mönchengladbach, the most common combination was Christian Clemens to Sam. Sam himself also completed the most passes of any player in the final third of the pitch.

Injuries have plagued Sam’s career ever since his switch from Hamburg to Leverkusen in 2010. In one season he had four muscular injuries, and during his time with Bayer he missed 54 matches on the sidelines.

When joining Schalke, he told fans he was in better shape than ever before. For Sam’s career to continue at the high levels he and everyone else expects, the recurrence of his muscular woes will need to be avoided.

They said…

Upon his move to Schalke, rent-a-quote general manager Horst Heldt couldn’t wait to sing the praises of his new man. "He’s a player who can play in a variety of different positions and has said he wants to win everything possible with us," said the outspoken chief. "We’re very pleased to get such a talented player."

Joachim Löw, who handed Sam his Germany debut in May 2013, has also mentioned Sam’s confidence being one of his best assests, saying: "He’s not cocky, just very confident. It’s something that you might think he’d struggle with considering his injuries, but he knows he has the ability and it shows."

Did you know?

All players have their own pre-game rituals. Some get in the mood with music, others with energising food perhaps, or even a nap. For Sam, however, it’s all about watching videos of Messi, Ronaldo and Robben.

"Before every game I go on YouTube for about half an hour and watch the best players in the world for inspiration," he admitted. He's been doing it ever since Robben arrived in the Bundesliga with Bayern, and added: "These videos are now more in my subconscious. I act on instinct with the ideas from the videos. It’s like another part of training for me."

TALENTSPOTTER RATINGS

Shooting 8

Heading 5

Passing 7

Tackling 6

Pace 9

Dribbling 8

Creativity 9

Work-rate 7

What happens next?

At 26, the German winger has plenty of time to prove himself, and an injury-free season is what he really needs. Despite not being able to complete a full campaign since his move from Hamburg to Leverkusen, Sam is still on the fringes of Löw's Germany squad.

With the young players around him champing at the bit for game time, consistency will be key – as will showing his best in the big games, starting with their Champions League game at Chelsea.